1. Field of the Invention
The present invention relates to the field of electrochemical molecular detection, such as the detection of nucleic acid polymerization, by detection of a charged particle (e.g. proton) by means of a sensitive electrical circuit. The present invention has particular application to nucleic acid sequence detection and enzyme substrate modification detection.
2. Related Art
Rapid, sequence-specific DNA detection is essential for applications in medical diagnostics and genetic screening. Electrochemical biosensors that use immobilized nucleic acids are especially promising in these applications because of their potential for miniaturization and automation. Current DNA detection methods based on hybridization rely on various optical, electrochemical or mass readouts. (Refs. 1, 2) However, direct, label-free electrochemical detection methods are not available.
A variety of electrochemical methods have been described, all of which detect direct electronic signals using various electrochemical reactions during DNA hybridization at the electrode surface. (Refs. 1, 2, 6) In contrast, current detection and sequencing-by-synthesis technique requires the use of several enzymatic and photochemical steps. (Refs. 7, 8) Thus a direct electrochemical detection method for this technique would greatly simplify the detection process and accelerate its implementation for rapid DNA sequencing and diagnostics. Described below is a label-free electrochemical detection method, Charge Perturbation Detection (CPD), applied to sequencing-by-synthesis.